In the field of automotive engine control units (ECUs), it is known for such ECUs to rely on a large amount of data to ensure that the engine operates optimally across a broad range of conditions. Such data is typically stored within on-chip flash memory, and the data is required to be updated or modified, sometimes referred to as ‘tuned’, whenever a new ECU is developed, or whenever an existing ECU is required to control a new engine, etc. This ‘tuning’ process is generally known as calibration, and conventionally comprises the use of hardware components to re-map parts of the on-chip flash memory to overlay memories that are typically implemented as random access memory (RAM) external to the ECU.
“Cold-start calibration” is the process of tuning the calibration data specifically to optimise engine performance when starting from a (usually extremely) cold temperature condition. The vehicle is typically required to be left overnight to reach the very low temperature conditions necessary for cold-start calibration. In addition, it is important that the ECU (or any part thereof) is not powered up in advance to avoid any heating effects that could potentially change the cold state behaviour, and that the operation of the ECU during calibration does not differ significantly from normal operation. Furthermore, any interaction with the ECU prior to, or during, the cold-start calibration procedure that is not part of the normal (i.e. production) start-up procedure (for example by way of an external calibration tool or the like) is undesirable, as this too may affect the validity of any calibration performed.